Gaseous fuels, such as propane, have found wide acceptance in household and recreational vehicle use. Such fuels are commonly used in association with gas grills, and other similar devices.
Heretofore, a consumer would typically purchase a pressure vessel, commonly known as a "cylinder", containing a certain nominal initial weight of gas. For example, a gas grill will commonly use a 20-pound cylinder. In any event, it is necessary to reduce the pressure of the gas within the cylinder, before delivering a supply thereof to the particular appliance to be fueled. This function has been accomplished by mounting a valve on the cylinder. A pressure regulator is commonly mounted downstream of the valve, and functions to reduce the pressure of gas flowing through the valve.
In recent years, the safety of such devices has been reviewed by various certifying agencies. The stored volume of gas is a fire hazard and, under appropriate conditions, is potentially explosive. To minimize the risk of fire, and because of increasing environmental concerns, it is generally desired to minimize the escape or loss of gas when the appliance is connected and disconnected from the cylinder. This is commonly performed by the homeowner, such as when it is necessary to have his cylinder refilled. In this event, the consumer will typically uncouple the cylinder and valve from the regulator, and take the cylinder to a suitable filling station to be recharged. After this has been accomplished, the consumer will take the cylinder back to the site, and reconnect it to the regulator and appliance.
Accordingly, it would be generally desirable to provide an improvement for a cylinder valve that will insure adequate sealing with a separable male connection inserted therein, and that will minimize the loss or escape of gaseous fuel when the cylinder is disconnected and re-connected to the regulator. At the same time, it would also be desirable to limit an unusually large flow from the cylinder, such as after a gas supply line or conduit has been inadvertently severed.